Refrigeration



.Feb. 7, 1939. w KGEL v 2,146,076

REFRIGERATION Filed Sept. 12, 1934 2 Sheets-Sheet l 4 x MZ %W F .I. ev 7 7 Feb.` 7, 19 39. w KGEL 2,146,076

REFRIGEHATION Filed Sept. 12, 1934 2 ?beats-Sheet 2 www/m V Patented Feb. 7, 1939 UNITED STATES REFRIGERATION Wilhelm Georg Kgel, Stockholm, Sweden, as-

signor, by mesne assig'nments, to Servel, Inc., Dover, Del., a corporation of Delaware Application September 12, 1934, Serial No. '743,656 In Germany September 30, 1933 15 Claims.

My invention relates to refrigeration and more particularly to the dissipation of heat from an artificial refrgerating system. Still more particularly my invention relates to refrigerating systems of the kind using an inert gas into which the refrigerant difiuses in its vaporization.

The 'principal object of the invention is to provide an absorber or other heat rejecting member of a refrigerating system, and more particularly o for systems of the no moving part type in which the manufacture is facilitated while at the same time heat transfer is improved.

A further object of the invention is to provide better heat transfer between the heat rejecting 3 part or parts of a refrigerator and the air of a natural draft flue for conducting away the rejected heat.

The invention will be understood by reference to the following description taken in conjunction with the accompanying drawings which form a part of this. specification, and of which:

Fig. 1 is a rear view of a refrigerator with the back plate of the flue removed; and

Fig. 2 is a vertical transverse sectional view i taken on the line 2-2 of Fig.` 1.

The refrigerator includes a liner o enclosing a food space ll access to which may be had through the usualdoor or doors. Within the space ll is: an evaporator l2. surrounding the liner is insulation l3 and around the insulation is a shell M.

At therear of the refrigerator is an apparatus i compartment !5 which also constitutes a flue for upward flow of cooling air. The back of the flue is formed by a substantially solid plate IS which' has louvres I'l for 'the outlet of cooling air. Air is admitted to the flue l5 at the bottom and due to theheat given of! by the refrigerating ap- 'paratus, flows upwardly through the flue and i out at the top through the louvres l'l cooling the 'heat rejectingparts of the refrigerator.

'The' apparatus includes a generator s which maybe vertically disposed in the space .15 and which has 'a central flue pipe IS. The generator is' enclosed' in an insulation casing 20. A burner 21 is provided below'the flue !9 and directs -a flame into the 'flue' to heat the' generator. The

flue is continued upwardly at 22 and hasan out- 4 let' 23`in the top of `the cabinet. surrounding the 60"lower`-part of the flue !9 which is extended outside of' the generator proper is a thermosyphon 'coil 24 wound around the'flue in good thermal contact.- A thermosyphon riser tube '25 extends 'up'wardly mm the top =of `coil 24' to` the upper* 65 or vapor space of generator s. A conduit 26 is i different banks are inclined slightly to the horiclined to the verticalas shown in Fig. 1.'

banks 36 and 3'l are in planes which are inclned 'to the vertical as best seen in, Eig. 2. These L planes are, however parallel to facilitate manui It will be seen that in vertical projection the fins y -'I'he absorbermay bemadeup by. forming a series of U-bends -with the legs i slightly off v parallel toallowvfor the 'ultimate inclinatiom The fins PATENT OFFICE connected to the lower part of the generator and to the outer conduit 21 of a liquid heat exchanger 28. An inner conduit 29 of the liquid heat exchanger 28 extends from the bottom of an absorber reservoir 30 to the bottom of coil 24. 5 Heat'exchanger 28 is enclosed in an insulation casing 31. A pipe 32 connects the outer pipe 21 of the liquid heat exchanger with the upper part of an absorber designated generally by reference character A.

The absorber is Situated in the flue |5 and consists of a coil of relatively large sized tubing 33 adapted for continuous downfiow of liquid therethrough. The lower end of the absorber A is connected to conduit 34 which is in turn conll nected to the absorber vessel 30.

The absorber includes a plurality of banks of tubes or tube portions as best shown in Fig. 2. While any number of banks may be provided,.for the particular refrigerator shown there are two banks, 36 and 31. Each bank includes a plurality of tube portions which are preferably straight. The tube portions of bank 36 are inclined slightly from the horizontal in one direction and the tube portions of bank 31 are nclined slightly from the horizontal in the opposite direction. The lower end of any straight tube portion is slightly abovecthe high end of the adjacent tube portion in the adjacent bank and the return bends connecting the adjacent tubes of o zontal. It will thus be seen that there is a slight and continuous decline throughout the absorber tube. r r

Fins are provided on the absorber' banks. -In accordance with the invention separate fins, are used for the irdividualbanl zs.` The fins on bank 36 are lettered 39 and the fins on banka] are lettered 40. Fins 39 are perpendicular to the tubes on bank 36 while fins 40' are perpendicular to the tubes of bank 31. Thus the fins are in- The fins 40 are inclined to one-side and thefins 39 are inclined to the otherside. Furthermore, the

facture, though thisnis notzcntirely necessary.

can -be then threaded on to thelegs of the U- bends and are perpendicular thereto whereby they can be readily secured tightly to the tubes as by being forced thereon or by expanding the tubes after the flns are on the tubes. Due to this arrangement good contact can be had. with the tubes and at the same time manufacture is facilitatd. Furthermore, an improved heat transfer between the tubes and the air is obtained as will be later explained.

The upper part of the absorber A is connected to one space of a gas heat exchanger 42 which is in turn connected with the evaporator l2. The conduit 34 is connected to a separate space of the gas heat exchanger 42 and connected to a different part of the evaporator. The gas heat exchanger and evaporator may be of various forms and the details of construction need not be given for purposes of the present invention. For more detailed information as to this general type of system reference may be made to U. S. Patent No. 1,609,334 granted Dec. 7, 1926, on an application of von Platen and Munters.

A refrigerant vapor pipe 44 is connected to the upper part of the generator !8. Fins 45 are disposed on pipe 44 to give an initial rectiflcation of the generator vapor. surrounding conduit 44 is a second rectifier jacket 48 which is supplied with condensed refrigerant from the condenser. Conduit 44 extends upwardly and is connected at the top of th refrigerator to condenser pipe 41. The condenser consists of the pipe 41 having fins thereon and is generally designated by reference character C. The condenser may be made in the same way as the absorber, although it is understood that the invention may be applicable either to the condenser or the absorber individually. The condenser shown includes two banks of tubes 'or tube portions 49 and 50. The tubes of these banks are inclined oppositly to the horizontal to provide flow of liquid downwardly through the condenser. Bank 49 has flns 5! thereon and bank 50 has flns 52 thereon. Fins 5I, as can be seen in Fig. 1, are inclined slightly from the vertical in one way and flns 52 are inclined slightly from the'vertical in the other way. The banks 49 and 50 are themselves in planes which are inclined from the vertical as shown in Fig. 2 and' the flns may overlap vertically as in the case of the absorber fins. The condenser drains into a c ber 53 from which a liquid conduit 54 carries liquid to the evaporator through the gas heat exchanger 42. A conduit 55 is connected to vessel 53 and is connected to rectifier jacket 46 for supplying liquid ammonia thereto. vapor generated in the rectifier jacket 46 is conducted back to the condenser in known manner, as by being conveyed through conduit 44.

Air is admitted to the bottom of flue I! and due to the heat given ofl is raised by natural draft through'the flue 15. The air passes over the absorber and condenser surfaces andwithdraws the heat to be rejected from the system. If some of the air' be followed in its upward course it will be seen that it will strike the fins 45 and its course will be changed from the vertical to an inclined course. As this air rises it then comes in contact with' the flns 39 and the course is changed in the opposite direction. Thus the air is givena sort of corkscrew path of travel and -the air is thoroughly stirred, which gives goodheat transfer. Even though the same air does not'contact the fins of thedlflerent bankathe The same effect takes place in the condenser, the air being twisted off the vertical on one side and twisted off the vertical on the other. This gives a complete stirring of the gases and prevents layers of air forming. 5

It will be appreciated that the condenser can be made in the same manner as the absorber. Either the banks can be made up separately and the return bends welded on to the straight portions of the tubing to which the fins have been 10 applied or the tubing can be made up in the form of U-bends, the fins applied to the separate banks, and then the remaining return bends welded on. It is also possible to apply the fins on the tubing with the return bends perpen- 15 dicular to the planes of the fins and then twist the tubing before the fins are pressed into contact with the tubing. The tubing may be expahded against the fins by drawing a steel ball through the tubing.

While the general internal operation of the system is the same as in other systems of this character, it may be well to explain the internal cycle. Heat applied to the generator !8 separates refrigerant vapor from solution. The re- 25 frigerant may be ammonia, the solvent may be water, and the auxiliary gas may be hydrog'en. Refrigerant vapor passes through conduit 44 and entrained water vapor is condensed in the inclined conduit 44 due to the rectifier fins 45 and the rectifier jacket 45, the condensed water returning back through the tube 44 to the generator. Substantially pure refrigerant vapor passes to the condenser and is there condensed. The liquid flows downwardly into vessel 53 and thence 35 through the conduit 54 and through the gas heat exchanger into the evaporator l 2. The evaporator may include theusual ice trays. In the evaporator the refrigerant evaprates and difiuses into the inert gas. The gas mixture thus formed, 40 which may be ammom'a and hydrogen, passes through the gas heat exchanger and into the lower part of the absorber. The gas mixture passes upwardly through the absorber in contact with a downwardly flowing stream of liquid. 45 The weak liquid, namely water deprived as much as possible of its content of refrigerant, is supplied to the absorber through conduit 32'. The liquid flows downwardly through the pipe of 'one bank then across to the other' bank and back to 50 the first bank, and so on gradually down through the coil. If desired wire mesh vor' other capillary material or distributing material may be employed in the absorber to hinder the flow of liquid or to increase the available contact surface be- 55 tween gas and liquid. The weak absorption liquid absorbs the refrigerant vapor and releases the inert gas. The weak inert gas passes, upwardly 4 through the absorber and through the gas heat exchanger 42 into the evaporator to become enoo riche d by further refrigerant vapor.

` The enriched liquid flows from the bottom of Kthe absorber into the vessel 30 and thence flows through conduit 29 and is lifted by the thermosyphon coil 24 to the generator. By this means 05 a suflicient height is maintained in the generator so that the weak liquid can flow through conduits 25, 21 and 32 to the upper part of the absorber.

various changes may be made withoutdepart- 70 ing from the spirit 'or scope of the invention. The louvres l'l may, for example, be disposed in the top of the flue !5 instead of on the side. The flue gases may be discharged into the flue ,15. various changes may be made in the construc- 'll tion of the apparatus. It is not absolutely necessary that separate flns be used on the different banks but it will be appreciated that the utilization of the same flns would be less adaptable to manufacture. For example, flns might be employed which could span the banks and rhichwould have weak intermediate parts whereby the absorber tubes could be twisted to give the different angularity of the extended surfaceon the diflerent banks. While flat piates are used for the fins it will be appreciated that these may be corrugated vertically, transversely, or in any other manner to further stir up the flowing air.

What I claim is: c

1. In a refrigerator', walls forming a vertical air flue and a heat rejecting member in said flue including a plurality of groups of flns,-the flns of one group being inclined from the vertical one way with respect to a given vertical plane, the flns of an adjacent group being inclined from the vertical the other way with respect to the same vertical plane, and the flns o! both groups being inclined from the vertical with respect to a plane at right angles to the first-mentioned plane.

2. In a refrigerator, walls forming an air flue 'and a heat rejecting member in said flue including a plurality of banks of tubes arranged in paralle with respect to flow of air through the flue, and separate groups of flns on the different banks, the' groups of flns being diflerently inclined to the general direction of flow of air through the flue.

3. In a refrigerator, walls forming an air flue and a heat rejecting member in said flue including a plurality of banks of tubes, and separate groups of flns on the different banks, said banks being arranged in parallel with respect to flow of air in the flue and the flns of one group inclined with respect to the flns of another group.

4. In an absorption re'frigeration apparatus, a gas heat exchanger, a storage vessel, a vertical conduit extending between said exchanger and said vessel, and an absorber coil having one end connected to said conduit and one end connected to said exchanger, said coil having flns thereon inclined to the vertical.

5. In an absorption refrigeration apparatus, a gas heat exchanger, a storage vessel, a conduit extending vertically between said exchanger and said vessel, and an absorber coil having one end connected to said conduit and one end connected to said exchanger, said coil having flns thereon inclined one way from the vertical and flns thereon inclined the other way from the vertical.

6. In an absorption refrigeration apparatus, a gas heat exchanger, a storage vessel, a conduit extending vertically between said exchanger and said vessel, and an absorber coil having one end connected to said conduit and one end connected to said exchanger, said coil including a plurality of banks of tubes and oppositey inclined flns on the diflerent banks. i

7. Refrigerating apparatus including a generator, a condenser, an evaporator, an'absorber,

and members connectlng the atoresaid parts, to

form a complete system for circulation of a re- 'frigerant, an absorption liquid and an inert gas,

members forming an air passage, said absorber being positioned in said air passage, and said absorber including a plurality of banks o! tubes arranged in parallel with respect to flowof air in said passage, the banks being oblique to the general line of airflow through the passage and the tubes of one bank being oblique to the tubes of another bank. and air cooling 'flns on said tubes perpendicularly to the tubes.

8. Refrigerating apparatus including a generator, a condenser, an evaporator, an absorber, and members connecting the aforesaid parts to form a complete system for circulation of a refrigerant, an absorption liquid and an inert gas, members forming an air passage, said condenser being positioned in said air passage, and saidcondenser including a plurality of banks of tubes arranged in parallel with respect to flow of air in said passage, the banks being oblique to the general line of air flow through the passage and the tubes of one bank being oblique to the tubes of another bank, and air cooling flns on said tubes perpendicular to the tubes.

9. A refrigerator including walis forming a thermally insulated storage compartment and a relatively narrow natural draft air flue at one side of said storage compartment, and refrigeration apparatus including a boiler, a condenser, an evaporator and an absorber interconnected for flow of refrigerant, absorption liquid and inert gas, said absorber being disposed in said flue and comprising tubing adapted for continuous downward flow of liquid, different parts of said tubing being difl'erently inclined, and flns on the diflerently inclined parts of the absorber tubing, the flns on tubing of one inclination being oblique 'to and alongside of flns on tubing ot another inclination, whereby air passing oversaid tubing is diverted in a plurality of parallel paths having difl'erent directions, and connections to supply and withdraw absorption liquid and inert gas to and from said tubing.

10. Refrigerator including walls forming a thermally insulated storage compartment and a relatively narrow apparatus compartment at one side of said storage compartment, substantially coextensive therewith in height, and torming a flue adapted for upward flow of air therethrough, and refrigeratlon apparatus including an absorber which is relatively flat and located in said flue formed by the narrow apparatus compartment and cooled by substantially verticaliy flowing air therein, said absorber coniprising banks of tubes, said banks being located substantially side by side, each bank having a group of flns inclined oppositely to another.

11. Refrigeration apparatus including a generator, a condenser, an evaporator, an absorber, and members connecting the atoresaid parts to form a complete system for circulation of a refrigerant, an absorption liquid, and an inert gas, members Iorming an air passage, said absorber being positioned in said air passage, and heat transfer surface members !orming part of said absorber, said members being arranged in parallel with respect to air flow at a givcn cross sectional plane transverse to the general line of air flow, and said members which are arranged in parallel with respect to air `flow being oppositely inclined relative to and at the same said cross sectional plane to divert airbeing heated in said passage in a plurality of directions from the general line of air flow therethrough.

12. Refrigeration apparatus including a generator, a condenser, an evaporator, an absorber, and members connecting the aforesaid parts to 'form a complete system tor circulation of a re'- frigerant, an absorption liquid, and an inert gas, members forming an air passage, said absorber V being positioned in said air passage. and heat transfer surface members torming part ot said absorber, said members being arranged in parallel with respect to air flow at a given cross sectional plane transverse to the general line oi air flow, and said members which are arranged in parallel with respect to air flow being oppositely inclined relative to and at the same said cross sectional plane to divert air being heated V in said passage in `a plurality of oblique directions from the general line of air flow therethrough.

13. Refrigeration apparatus including a generator, a, condensei', an evaporator, an absorber, and members connectlng the aforesaid parts to form a complete ;system for circulation of a refrigerant, an absorption liquid, and an inert gas, members forming an air passage, said absorber being positioned in said air passage, and a plurality of groups of heat transfer surface members forming part' 'of said absorber, said groups being arranged in parallel with respect to air flow at a given cross sectionalplane transverse to the general line oi' air flow, and said groups which are arraned in parallel with respect air flow being oppsitely inclined relative to and at the same said cross sectional plane to divert air being heated in said passage in a plurality of oblique directions from the general line of air flow therethrough.

14. In absorption reirigeration apparatus including an evaporator and an absorber through which an inert gas is circulated, the improvement which consists in flowing absorption liquid in a continuously downward path of flow, cooling said path o! liquid flow by air, and causing the air in its passage over said path of liquid flow to be deflected into a plurality of parauel paths of flow, said paths of flow being oblique with respect to the general direction of air flow and at diflere: t angles with respect to each other at their places of parallel flow.

15. In absorption refrigeration apparatus including an evaporator and an absorher through which an inert gas is circulated, the improvement which consists in flowlng absorption liquid in a continuously downward path of flow, cooling said path of liquid flow by natural draft, and deflecting flow oi air in its passage over said path of liquid flow in a pluralityof parallel paths of difi'erent directions relative to each other and oblique to the general line of air flow at their places of parallel flow.

WILEELM (mono KGEL. 

